I just replaced whole groupset and cables with new everything but the shifters.
Still fine tuning as its only a day old but found there is the same non/delayed shift going down round about 5-4 on the cogs as on the old groupset.
The only thing that has not changed is the shifter so just wondering if there is any thing replaceable/serviceable in a shifter or do I fork out for new?

Interested in this, my shifters have been used on 2 or 3 groupset now i wonder what the life expectancy is for shiters ?

I’ve worn two Deore shifters out – they stop ‘holding’ on the ratchet when you shift. Took about 5 years commuting…

Yeah fairly common. The shifters do most of the work really. Old 10sp 105 shifters can go wooly very quickly.

What are the old shifters and what’s the new groupset?

IME using them with sticky / corroded cables (so,etimes without realising) kills them as well

BBS +1

Mech hanger alignment check before firing the parts cannon at it

I’ve yet to see a shifter cause this.

Ime when a shifter goes. You know about it.

I’ll take hanger or poorly routed cable

Agreed that hanger alignment or roached cables are most likely cause, but interested to hear what the parts mix is in case there’s a shifter/mech incompatibility – even though there’d be issues right across the cassette if that was the problem.

Shifter is Deore XT RAPIDFIRE Plus Shift Lever (11-speed) and has been for last two years.
Cassette is XT 11-40 and RD is XT M8000 GS.
Everything is as was just new apart from the shifter.
Cables are Shimano inner and outer cut to same length as old ones.
Oh and yes the Shadow lever is on.
Perhaps its the low air temp on new components? The grease just to viscous for the freezing conditions in sunny Devon at present.

has been for last two years

that’s quite short.

Had problems with older Shimano XT 10-speed shifters.
To avoid this: with new shifters I take the cap off, put “not too thick” – but lots of – bearing grease in and put the cap on again.

Was worried in the beginning that the plastic parts might suffer from grease and that I might get problems at low temperatures.
But no problems.
Think the grease helps to keep dirt and crap out of the unit (bike in very muddy conditions as well).

Oh and yes the Shadow lever is on.

presume you mean clutch?

check alignment, your old rear mech might have been bent and been adjusted to compensate. if the issue is one end of the cassette or the other it’s generally an alignment issue. unless its Sram NX as they tend to have very dodgy pivots that bind especially after a knock and don’t come back down the cassette

To avoid this: with new shifters I take the cap off, put “not too thick” – but lots of – bearing grease in and put the cap on again.

shimano freehub grease is good